Update src/content/docs/warp-client/get-started/linux.mdx

Author: ranbel

src/content/docs/warp-client/get-started/linux.mdx

@@ -50,6 +50,10 @@ You can switch the protocol that WARP uses to route traffic from the device to C
 - **WireGuard:** `warp-cli tunnel protocol set WireGuard`
 - **MASQUE:** (default) `warp-cli tunnel protocol set MASQUE`
 
+:::note
+The protocol values are case-sensitive.
+:::
+
 For information on WireGuard versus MASQUE, refer to our [blog post](https://blog.cloudflare.com/zero-trust-warp-with-a-masque).
 
 ### Using 1.1.1.1 for Families